PURPOSE: To ensure a superconducting coil having greater floating force by constructing the coil by attaching a conductive thin film on an insulating film and winding the same spirally, and setting the thickness of the thin film to be less than the depth of a skin effect of resonance frequency.

CONSTITUTION: A spiral thin film resonance coil 4 is constructed by spirally winding into many layers an insulating film 2 on which a conductive thin film 1 is attached. The thickness of the conductive thin film 1 is set to be less than 1/3 of the skin depth of a resonance frequency W. The spiral resonance coil 4 is supplied with power through a predetermined circuit when used as a superconducting coil. More specifically, the spiral thin film resonance coil 4 is supported by a cryostat 11 so as to be rendered to an induction from an external induction coil 13 and the induction coil 12 is supplied with a current from a power supply 13. Accordingly, a predetermined equivalent circuit is formed between the spiral thin film resonance coil 4 and the external induction coil 12. Hereby, there is ensured a high magnetic field current having stable and greater floating force without causing any eddy current.